The Chesapeake Bay watershed touches six states and is home to 17 million people and almost 84,000 farms and ranches. Agriculture contributes about $10 billion annually to the region's economy, USDA said.

Report finds Chesapeake Bay watershed projects lowered the estimated average edge-of-field losses of sediment by about 15.1 million tons a year (USDA photo)

The report, released Thursday, is part of the NRCS Effects Assessment Project. It is based on farmer surveys, natural resource information and advanced modeling techniques to assess the effects of conservation practices on cultivated cropland.

Since 2006, the report found, conservation practices applied by farmers and landowners are reducing nitrogen leaving fields by 48.6 million pounds each year, or 26%, and reducing phosphorus by 7.1 million pounds, or 46%.

The report notes that these practices have also lowered the estimated average edge-of-field losses of sediment by about 15.1 million tons a year, or 60% – enough soil to fill 150,000 railcars stretching more than 1,700 miles, USDA said.

Additionally, due to efforts of the Chesapeake Bay Watershed Initiative, developed by USDA in 2008, there has been wider acceptance of innovative conservation practices, USDA said. Notably, some form of erosion control has been adopted on 97% of cropland acres in the Chesapeake Bay Watershed.

The report also shows an increased use of cover crops by Bay watershed farmers. Since 2006, land with cover crops in a cropping system increased from 12% of acres to 52%. Farmers are using a variety of other conservation practices, such as no-till, that help keep nutrients and sediment on fields and out of nearby waterways.

Conservation groups like the National Association of Conservation Districts, said the report demonstrates that producers' voluntary use of good conservation practices is paying off in a big way in the watershed.

"The report highlights the importance of conservation planning," said NACD President Earl Garber. "No single practice applies for every producer on cultivated cropland; the use of a comprehensive conservation plan has been critical to these water quality successes."

However, USDA Secretary Tom Vilsack pointed out that a majority of the conservation practices in the Chesapeake Bay were made possible through Farm Bill conservation programs, which are now expired.

"This report demonstrates that voluntary conservation practices made possible through the Farm Bill can have a substantial impact on limiting nutrient and sediment runoff from farms in the Chesapeake Bay Watershed and across the nation," Agriculture Secretary Tom Vilsack said. "These conservation efforts help to clean our soil and water, boost outdoor recreation that adds more than $640 billion to our economy, and ensure that agriculture has the tools to remain productive in the years to come."